Have her check with police departments that have K9 units . . . she may be able to adopt one that is being retired or taken out of service. It would already be trained in police tactics and protection, and she can give it additional training as a service dog to retrieve items, carry dog saddlebags, etc. to make her life easier.
Of course, she'd want to make sure she didn't get one that was being rejected for unpredictability or being overly-aggressive. A department or training organization that was close enough that her son could take her to visit would be ideal. The K9 handlers are used to doing school programs etc and so are usually real friendly and very enthusiastic about showing off their K9 companions.